History- Vietnam War

Please write a research paper on the following History Questions in form of an essay. Questions should be well answered in progression from first to last in 3-4 pages.

Explain how and why the United States became involved in Vietnam, and how that involvement led to the Vietnam War? Why was the war so controversial in the United States? Why did the United States ultimately decide to leave Vietnam? What is the legacy of that war? How were the American People and the nation transformed by this experience?